I am tinkering with some solenoids and have read that solenoids should be momentary only or they could be damaged.
Is there any rule of thumb as too how long you could keep one energized before you cause damage? .5 seconds....5 seconds...30 seconds?
Just wondering
It's just an electromagnet - why would it care how long it was activated for?
Unless the current flow is really high and heating is a concern.
Most solenoids are driven well beyond their continuous rating because they are doing
an occasional action, like operating a door lock. Otherwise the solenoid would have to
be much bigger and more expensive.
There is no rule of thumb, there is physics. You need to know the power in and model
the ways heat can leave (conduction, convection and radiation). A datasheet should
give a rough guide to the degC/W, saving you from measuring or calculating this.
Sometimes you see max duty cycle at rated current.
gruant2000:
I am tinkering with some solenoids and have read that solenoids should be momentary only or they could be damaged.Is there any rule of thumb as too how long you could keep one energized before you cause damage? .5 seconds....5 seconds...30 seconds?
Just wondering
Actually, your comment about rule of thumb is appropriate. If you can keep your thumb on the solenoid while it is operating, then it is still ok. If you burn you thumb, then the solenoid is on too long. Do you know where the solenoids came from? That will give a clue about how long they can be energized.
As an example, I used to have a component sequencer that used 24 volt DC rotary solenoids to move a reel of components one component space. They were pulsed with 110 volt dc for just a fraction of a second and they operated that way for years.
My home irrigation system has 120 volt AC solenoid operated water valves that are energized for perhaps 20 minutes to 5 hours. They have been in use for 6 years.
Paul